1. Field of the Invention
The present invention relates to a recording tape cartridge accommodating, within a case, a single reel on which is wound a recording tape, such as a magnetic tape or the like, which is used as a recording/playback medium mainly of computers or the like.
2. Description of the Related Art
Conventionally, magnetic tape cartridges have been known in which a magnetic tape, which is used as a data recording/playback medium of a computer or the like, is wound on a single reel, and the reel is accommodated in a case. A leader member, such as a leader pin, a leader tape, or a leader block, is provided at the distal end of the magnetic tape. A pull-out mechanism provided at a drive device pulls the leader member out from an opening of the magnetic tape cartridge, and winds the magnetic tape, which is fixed to the leader member, onto a take-up reel of the drive device.
A reel gear is formed in an annular form in the center of the bottom surface of a reel which emerges from an open hole formed in the bottom surface of the magnetic tape cartridge. Due to a driving gear, which is provided at a rotating shaft of the drive device, meshing with this reel gear, the reel is driven to rotate. By rotating the reel of the magnetic tape cartridge and the take-up reel of the drive device synchronously, data can be recorded onto the magnetic tape, and data recorded on the magnetic tape can be played back.
Such a magnetic tape cartridge requires little space for storage thereof, and a large amount of information can be recorded thereon. As shown in FIGS. 9 through 11, the position of the opening and the type of the door which opens and closes the opening differ for each type of leader member. Namely, in the case of a leader pin 60, as shown in FIG. 9, an opening 68 is formed in a side wall 64 of a case 62 which side wall 64 is parallel to the direction of loading the magnetic tape cartridge into a drive device (the direction of arrow P). The opening 68 is opened and closed by a door 66 which slides in the same direction as the loading direction.
However, when the opening 68 is provided at the side wall 64 of the case 62 in this way, the pull-out mechanism of the drive device must pull-out the leader pin 60 by circling around from the left-right lateral direction of the case 62. Thus, space for the pull-out mechanism to circle around must be ensured at the drive device, the mechanism for making the pull-out mechanism circle around is complex, and a drawback arises in that the drive device becomes large. Further, there is also the problem that the pull-out path of a magnetic tape T becomes long.
Moreover, in the case of a leader tape 70, as shown in FIG. 10, an opening 78 is formed in a front wall 74 of a case 72 which front wall 74 is perpendicular to the direction of loading the magnetic tape cartridge into a drive device (the direction of arrow P). A door 76 which opens and closes the opening 78 is a rotatable-type door which rotates forward around a supporting shaft 75 supported in a vicinity of a corner portion of the case 72. However, when the opening 78 is provided at the front wall 74 of the case 72 in this way, although there is no need for the pull-out mechanism of the drive device to circle around, the door 76 opens widely toward the front. Therefore, space must be ensured at the drive device so that nothing interferes with the door 76 at the time when the door 76 opens the opening 78, and a drawback arises in that the drive device becomes large.
Moreover, in the case of a leader block 80, as shown in FIG. 11, an opening 88 is formed by diagonally cutting off a corner portion 84 at a front side in the direction of loading the magnetic tape cartridge into a drive device. The opening 88 is directly opened and closed by the leader block 80. However, when the leader block 80 opens and closes the opening 88 in this way, there is the problem that it is easy for the leader block 80 to become dirtied or scratched. Namely, the leader block 80 fits into a reel hub 86 of the drive device, and forms a portion of the reel hub 86. Therefore, there is the concern that, even if the leader block 80 is dirtied or scratched to the extent that does not cause problems when the leader block 80 is normally used as the door, it may become difficult for the leader block 80 to fit together with the reel hub 86, and problems in the conveying of the magnetic tape T may arise.
In addition, the leader block 80 is merely anchored at the edge portion of the opening 88. Thus, when the magnetic tape cartridge is dropped, there is the problem that the leader block 80 can easily come out from the magnetic tape cartridge. Further, because the leader block 80 is larger than the leader pin 60, there is the problem that there are more constraints on the configuration of the case. Thus, a leader pin 60, whose function is separate from that of a door, is superior to the leader block 80 which functions as a door as well.